All gods have theoretically infinite potential for generating piety. If you had an infinite dungeon you could keep generating and converting forever.

They are limited by the fact that every dungeon is too small to get more that 100, possibly 150 piety out of a regular run. This translates to a complete set of boons from one god or a choice of one or two before conversion.

Most Vicious dungeons have HEAPS more blackspace, monsters, levels, and other stuff that lets you generate piety.

EM, Taurog, Binlor, and sometimes MA can easily top 200. I've also gotten there with JJ and TT, and I'm not counting desecrations for any of these. And I'm talking about regular, non-vicious runs. GG and Drac not so much, but they're supposed to be stingy.

Hmm, I'm not so sure. Namtar doesn't have any more blackspace than any normal dungeon - less, actually, unless you have LEMMISI/BLUDTOPOWA or wall crushing ability - until you get to the underworld, at which point your deity is mostly irrelevant. Same for VHoS. Dragon Isles and Demonic Library do have a moderate amount of extra blackspace, but it's not accessible until the very end, when it is the least useful for piety generation. Naga City's deity setup is completely different from any other dungeon. The vicious Tower is the only dungeon where this is really true, but whether that works in your favor really depends on which deity you get first (hint: GG is hax when you're going to ding 15+ times, especially if you find Pactmaker second or third, but as usual the penalty for prepping him just ruins everything).

The reason deities are so important is because, once you are able to deal with their restrictions/penalties, they are a massive resource of stat boosts and/or recovery. Not worshiping deities is just wasting available resources, much like not buying items or not using glyphs. (And interestingly, the classes that primarily focus on items and glyphs - Tinker and Wizard - are probably slightly more powerful overall than the classes that primarily focus on deities - Paladin and/or Crusader. The Vampire is forced Faithless and IMO is one of the top three or four most powerful classes in the game.) Try beating a hard or vicious dungeon with Miser or Warmonger and you'll have just as much trouble as if you go Faithless - probably even more trouble, in the case of Warmonger (aside from a handful of really broken strategies).

I would still like to see more options for rewarding Faithless play - a big conversion point or gold bonus for desecrating an altar while an atheist would be nice. More encouragement early on for players to learn and rely on deities would be a good idea. (This is just an off-the-cuff idea that I haven't thought through, but elsewhere someone mentioned that deity choice is about as important as race and class - what if picking an starting deity, or only deliberately choosing to go faithless, were done at the same time as race/class choice?) And, of course, better balancing of deities to be useful at all stages of the game would be wonderful (both early and late dungeons, and early and late within a dungeon), but unfortunately unlikely to happen anytime soon, if ever.

It's not just all that's been said, allthough q3 is right about not using gods = forgoing a huge resource. Not just huge resource, but a pretty dependable huge resource which you can plan around.

Vicious lets you really see what the gods allow you to do, and how much easier it is with proper understanding of them. And piety generation, desecration benefits and all that plays a part in that. The original Naga City had you locked in with nine altars and ten bosses - any you could do it. Heck, I never even abused transmutation in there even back then. I could not have imagined by that point (without expirience with old Gaan'Telet and hundreds of hours sunken into it), that anything in the game is that powerful.

If anomalies like rogues, monks, triswords and such let you get through everything else you never get to see just exactly how powerful gods are, how much you can push them and all that. This is one of the reasons (edit) vicious fails as post-endgame, because what vicious really teaches is just how much power you are forgoing if you go faithles, and you're supposed to be learning that to a degree before you do them. Otherwise they're just a stepping stone.

Also, wamonger being sort of as hard as faithless is directly related to piety generation - warmongers have trouble worshiping piety farms like binlor, mysterea and JJ, have little interest in worshiping EM, have trouble worshiping TT to a degree, and only really work with GG, Taurog and Drac in certain combinations. (The other reason is that many classes are glyph dependent).

Miser or hoarder, on the other hand are also worship restricting badges - they lower the finer points of Mysterea because of limiting refreshment (hoarder), taurog because of inventory space (hoarder), drac and gg because of no conversion / lower ammount of conversion fodder (miser, hoarder), and so on and so forth.

And Tinkers are as good as they are for me mostly because all the extra items and gold makes them get more out of gods than other guys would by letting them use the boons more effectively, or gain piety more effectivly through conversion fodder. (Well among other things). Wizards can actually time their glyph conversions the best because they can get the glyph CP benefits while still having glyphs to use for refreshment, for example. (Not their strongest point, but it's there).